1. Field of the Invention
The present disclosure relates to a device for generating limit torque for a rotating mechanism, and particularly, to a device for protecting a rotating mechanism for performing a rotary motion by generating a rotational displacement when an external force having a certain torque or more is transmitted to the rotating mechanism, such as a joint of a robot manipulator.
2. Background of the Invention
A torque limiter for protecting a rotating mechanism for performing a rotary motion by generating a rotational displacement when an external force having a certain torque or more is transmitted to the rotating mechanism is provided to a joint of a robot manipulator, etc.
A conventional torque limiter is provided with a rotating portion and a fixed portion, and an elastic force of a spring between the rotating and fixed portions is generated when an external force is transmitted to the rotating portion. The elastic force of the spring blocks the rotation between the rotating and fixed portions until before the external force reaches limit torque. When the external force reaches the limit torque and is identical to or greater than the elastic force of the spring, a relative rotation of the rotating portion is generated with respect to the fixed portion.
The conventional torque limiter has a function of returning to its initial position after an external force generating a rotational displacement of the rotating portion is removed, but cannot deal with a random torque input according to changes of various environments and operating conditions. That is, the rotating portion is operated by only a specific external force defined by only the initial setup of the spring, and it is impossible to change limit torque with which the rotation of the rotating portion is started under various conditions.
Therefore, in the conventional torque limiter, the initial setup of the spring should be changed to change the limit torque, and hence the entire rotating mechanism should be disassembled.